Exploration: Using a Texture to Provide Surface Irregularity for Dynamics / C4d Feature Suggestion


#1

Yesterday I was testing out a material from TextureHaven. Specifically I wanted to see how well it’s displacement channel data would look in Octane render.

In this case–a very rock-crowded surface-- the displacement worked well. But only if I kept the camera from getting too low or too close. Not too surprising there.

Then I asked myself…how would a displacement texture work if I converted the displacement to mesh and used it to impact dynamics? Would the dynamics play well…and prove believable?

Today I’ll post an animation to demonstrate what I found. And also post a derivative suggestion for Maxon and its future dynamics system.


#3

Perhaps I am not quite understanding your objective Mate.

If you are doing rigid body collisions and using convex hull or mesh for the collision surface,
then a displaced surface baked to its irregularly shape mesh will only make dynamics simulation more computationally expensive yes??


#4

@ThreeDDude

I was indeed concerned that to achieve realistic physics my deformed mesh would be too heavy and the sim would be reduced to a crawl or even crash.

I was surprised how simple the solution was. Here is the work-flow:

  1. Use two planes, one with the 4k+ displacement that is rendered, and the second unrendered low res proxy to run in the simulation
  2. Bake the displaced plane then process with strong polygon reduction
  3. Eliminate polys that aren’t needful to interact with the simulation

Using this method the sim cached very briskly.


#5

Again, the rock texture’s displacement isn’t visually convincing w/the camera this low and close. That wasn’t the focus of this exploration.

The physics seem quite convincing, IMO.


#6

Now in conclusion the feature expansion that I suggest for Maxon to add with it’s physics system.

Currently one can change physics attributes like bounce, friction, drag etc on an object by object basis. I believe it would be a natural progression to enable maps to control such attributes.

Imagine being able to paint over a surface where things are slick or where there would be higher friction, etc.


#7

That looks amazing - great idea!


#8

Understood,
Actually I have used low poly proxies for years
for sending both objects and pre-animated
Characters over to Next limit Realflow to interact with the fluid solver
and replacing them with their high poly counter parts for the render.

Daz studio has quite an excellent Decimator plugin that get its figures down
to extemely low polygon counts while retaining the rigging for export as FBX or even MDD.

The new Iclone Character Creator 3 program, from Reallusion, has a similar function
for their Avatars

On the Matter of a feature in C4D that would enable control of collision properties
on a surface area by surface area basis, as one might imagine,this already exists in SideFx Houdini
in the form of “friction variable weight painting”.

I have never understood how we could have a fairly capable jiggle deformer
in C4D for ever a decade where the strength is controlled by a graduated weight map
on a portion of a surface.( belly,jowls etc)

Yet have a cloth & Rigid body system that does not recognize those weightmaps for
partial mesh/surface simulation.

Modynamics was a fun bit of play when it was introduce a decade ago.
I run quite an older version C4D… so tell me has modynamics
been updated at all for more precises controls like the rigid body parris solver in realflow??

…or have people simply resigned themselves to buying XP subscriptions
just as we character animators have resigned to investing MOBU or IClone/IKinema for serious Mocap based workflows ??


#9

C4D has added a lot of goodies over the years. I love it.

But yes, there are ways it comes up short esp. in character arena and high end simulations. I’m sure Maxon would readily admit that.

I expect we are going to start to see a lot of progress in some of these areas.

The fields, volumes and nodes expansion are a sign of things to come, IMO.